Benign Prostate Hyperplasia (BPH), also called prostate enlargement, occurs in almost all men as they age. About half of men in their 60s have at least some symptoms of BPH. The prostate is the semen-producing gland that surrounds the urethra, the tube that carries urine from the bladder out of the body. Symptoms of BPH result when the prostate gland grows to the extent that it blocks the flow of urine through the urethra. This blockage may cause urinary problems, including an inability to completely empty the bladder, a frequent urge to urinate, a weak urine stream, nocturia, and hematuria. In some cases, these urinary problems lead to more serious complications, including urinary tract infections; bladder damage, stones, or infection; and kidney damage.
Medications used to control prostate growth include alpha blockers and 5-alpha reductase inhibitors. Alpha blockers may act by relaxing the muscles around the bladder neck, which makes urination easier. Alpha blockers approved by the Food and Drug Administration to treat BPH are terazosin (Hytrin®), doxazosin (Cardura®), tamsulosin (Flomax®) and alfuzosin (Uroxatral®). The long-term effects of alpha-blockers are unknown and side effects include interactions with drugs taken to treat impotence and dizziness and lightheadedness upon standing. 5-alpha reductase inhibitors, such as finasteride (Proscar®) and dutasteride (Avodart®) act by shrinking the prostate. 5-alpha reductase drugs may only be effective in subjects with large prostates and not in subjects with moderately-enlarged or normal-sized prostates. In addition, 5-alpha reductase drugs may take up to a year to produce therapeutic effects, may decrease libido, and may interfere with accurate reading of PSA tests, which are used to diagnose prostate cancer.
Non-invasive procedures used to treat BPH include transurethral microwave therapy (TUMT), transurethral needle ablation (TUNA), interstitial laser therapy (ILT), and prostatic stents. TUMT, TUNA, and ILT involve the use of heat produced by microwaves, radio waves, and lasers, respectively, to destroy prostate tissue blocking the urethra. TUMT, TUNA, and ILT may be less effective for large prostates, and the long-term effectiveness of these procedures is unknown. Prostatic stents are metal coils used to prop open the urethra. Stents are typically used in subjects unwilling or unable to take medications and/or have surgery, and are typically not considered to be a long-term treatment option.
Surgeries to treat BPH include transurethral resection of the prostate (TURP), transurethral incision of the prostate (TUIP), laser surgery, and open prostatectomy. In TURP, a narrow instrument is inserted into the urethra and used to scrape away prostate tissue surrounding the urethra. TUIP is performed similarly to TURP, but only one or two cuts in the prostate are made to relieve the pressure on the urethra. Laser surgery, such as photosensitive vaporization of the prostate (PVP) and holium laser enucleation of the prostate (HoLEP) involve the use of lasers to destroy prostate tissue. In an open prostatectomy, the prostate is accessed through an incision is made in a subject's lower abdomen (rather than through the urethra), and the inner portion of the prostate is removed. A subject who undergoes surgery to treat BPH may require additional surgeries if the prostate grows back. Side effects, such as impotence, incontinence, infection and scarring, may occur.
Medications, non-invasive procedures and surgeries known in the art for treating BPH may not be as effective as desired and often produce side effects. Methods of treating subjects with BPH that are more effective than current therapies, e.g., surgery, are clearly needed.